1. Field of the Invention
The present invention relates generally to semiconductor wafer probes and, in particular, to a method and apparatus for removing and/or preventing contamination of a surface of the probe, typically around a working or distal end.
2. Description of Related Art
In the field of semiconductor manufacture, a semiconductor wafer must be tested to determine one or more of its electrical properties prior to or after the formation of integrated circuits thereon. An elastic metal gate (EM-gate) probe may be used to determine these electrical properties. Such a probe desirably includes an elastically deformable conductive tip for contacting a front surface of the semiconductor wafer. An electrical stimulus is applied between the elastically deformable conductive tip and the semiconductor wafer and a response is measured to the electrical stimulus. At least one electrical property of the dielectric and/or the semiconducting material of the semiconductor wafer is determined from this response. The conductive tip of the probe is formed from metal, such as tantalum, a conductive elastomer, a conductive polymer, etc.
One drawback to using an EM-gate probe is that a surface of the probe that contacts the semiconductor wafer may become contaminated. Such surface contamination is undesirable, since it adversely affects measurements. This contamination originates from the local and untreated atmosphere surrounding the probe, which is typically a mixture of numerous gases and gaseous vapors. Such vapors can condense on the probe surface and form a liquid or semi-liquid film. Although the constituents in the contamination layer are not precisely known, it is believed that water is a primary component. Other contaminants include various hydrocarbon molecules, which are typically referred to as organic contaminants.